The invention relates to a system for power supply to and switching of a number of electrical appliances each of which is provided with a functional power-consuming part and a switching part, comprising power conductors that are connected on the one hand to a power source and on the other hand to the electrical appliances and a signal line comprising at least one conductor, which is connected on the one hand to signal transmitters and on the other hand to the switching parts of the electrical appliances, each signal transmitter corresponding with the switching part of one appliance or a group of associated appliances and, when activated, generating a control signal peculiar to the corresponding switching part, which is addressed to that switching part directly, and a clock pulse generator connected to the signal line.
The invention relates particularly to a system whereby a given electrical appliance may be switched from each outlet of the signal line and so connected to a power source such as the mains.
`Functional power-consuming part` may relate to any electrical appliance such as a lamp, an electric space heater, a fan, an alarm horn, a drive motor of apparatus in a factory, on board a vehicle, boat or aircraft, and so forth.
A system of this type is known from U.S. Pat. No. 4,215,276. In this known system the signal line comprises a first conductor which is connected to the clock pulse generator which supplies a clock pulse signal to all signal transmitters and all switching parts, and a second conductor, the signal conductor proper, which interconnects all signal transmitters and switching parts, and which carries the control signals from the signal transmitters to the switching parts. Each signal transmitter, when actuated, allows a string of pulses peculiar to the signal transmitter and the corresponding switching part in a characteristic pulse format to pass from the clock pulse conductor to the signal conductor. This pulse signal is received by all switching parts but only the switching part which responds to the particular signal is activated.
This known system has the disadvantage that it requires separate conductors for control signals and clock pulse signals, which forms an undesirable complication. The object of the present invention is to provide a system that does not have this disadvantage.